|Authors: ||H. Lütken, E.B. Jensen, S.V. Wallström, R. Müller, B. Christensen|
|Keywords: ||growth regulation, non-GMO technique, ornamental plants, rol-genes|
Chemical growth regulators are commonly used in ornamental plant production to obtain compact growth.
The development of environmentally safe strategies to regulate plant growth is one of the future challenges as an increasing number of chemical growth retardants are expected to disappear from the market within a few years.
In the present study a non-GMO molecular breeding strategy was developed and evaluated during several years for a number of progeny generations (T1, F1, F1 derived breeding lines and F2 lines). We concentrated the development of this natural transformation technique on Kalanchoë blossfeldiana cultivars.
Firstly, using the naturally occurring bacterium Agrobacterium rhizogenes in a series of experiments, we documented that K. blossfeldiana ‘Molly’ transformed with rol-genes exhibited compact growth.
Secondly, it was confirmed by the authorities that, according to EU legislation, the avoidance of recombinant DNA techniques in the present approach results in plant lines classified as non-GMO. Thirdly, the focus of our research was the characterisation of the F1 and F1 derived progenies.
F1 lines were produced by crossings between selected T1 lines and the commercial Kalanchoë cultivar ‘Sarah’. To develop new breeding lines, F1-derived lines were produced by crossing F1 lines with other commercial cultivars.
Several series of promising breeding lines are the result.
A number of transformed lines were analysed genotypically and phenotypically.
We conclude that the non-GMO approach using natural transformation with A. rhizogenes is a valuable method to obtain compact ornamental plant lines.
Other quality criteria such as postharvest performance and ethylene tolerance can be influenced in a positive direction as well.
Natural transformation of Kalanchoë with A. rhizogenes and subsequent crosses result in compact progeny lines.
The characterisation of several progenies has given a thorough picture of the usefulness of this non-GMO breeding approach.
We evaluate that it can be used as an alternative strategy to chemical growth regulation.
Our results document that this technique is a valuable biotechnological method applicable in commercial breeding programmes.
Its usefulness in breeding strategies of other ornamental plants species has to be proven.
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